Welding apparatus



March 28, 1939.

R. K. HOPKINS 2,151,914

WELDING APPARATUS Filed Sept. 16,1936 2 Sheets-Sheet 1 INVENTUR ROBERTK. HOPKINS 7- fiw ATTORNEY March 28, 1939. R. K. HOPKINS WELDINGAPPARATUS 2 Sheets-Sheet 2 Filed Sept. 16, 1956 FIG. 3

m 0 B 6 H 6 l. 9 6 3 4433 211 m. a? 4M4 s 7 o E... 2 im 1 n w 5 9 a M 4a T o 3 TTORNEY ?atented Mar. 28 1939 t MED STATES PATENT OFFICE LDINGAPPARATUS Robert K. Hopkins, New York, N. Y assignor to M. W. Kellogg00., New York, N. Y.', a corporation of Delaware Application September16, 1936, Serial No. 101,103

14 Claims. (01. 219-8) This invention relates in general to electric Inaccordance with my invention I employ as fusion of metals and inparticular to the electric an electrode a metallic member, in the formof a fusion of metals for welding, veneering, and simsolid or a hollowbody, that is made up of the ilar purposes. major portion of one or moreof' the constituents .5 This application is a continuation in part of myof the metal it is desired to deposit, and separateapplication filedFebruary 18, 1936, Serial No. ,ly feed to the gap between the end of theelectrode 64,496. and the work, or in the vicinity of said gap, in theIn arc welding, as at present carried out, and in form of granules,pellets, wire, and the like, pref the veneering, or coating, of metallicsurfaces by erably through the electrode when it is a hollow 10 electricarc deposition of metal as disclosed in my body, the remainder of theconstituents required 10 application above identified, it is generallynecesto produce the desired deposited metal. The elecsary to employ asan electrode a body having a trode and the granules, pellets, wire andthe like, special composition so that the weld metal, or the are fed tothe gap between the end of the elecveneering metal, may have therequired compositrode and the work, at such rates that at subtion. Theelectrode is made of special composistantially each instant the properproportion of 15 tion primarily in order to obtain a weld metal orconstituents is deposited to produce the desired a veneering metal ofdesired composition while deposited metal. Thus, with any set of con..compensating for losses of the constituents of the stituents it ispossible simply by varying the meltelectrode in the arc and the dilutionof the metal ing rate and/or the rate of travel of the electrodedeposited from the electrode due to its penetraand/or the rate or ratesof feed of the granules, 20 tion into the metal being welded orveneered. pellets, Wire, etc., to obtain deposited metals of In thepresent cgmmercial practice, electrodes, widely difierent analysis.

Whether bare or covered, generally include all of The constituents ofthe desired deposited metal the constituents that they are to supply tothe e pp d t0 the p between t e end of the final deposited metal in thecore or metallic porelectrode and the Work, in their most economical 25tion of the electrodes even though it has long been r Thus. forinstance, When e si ed (18- proposed, in patents and in the literature,to inposited metal is an iron alloy the electrode is clude some of theseconstituents in the coatings made of mild steel or other equally cheapand of the electrodes. The proposals have not been readily availablematerial. If the desir d decommercially successful because of thedifiiculties posited metal includes chromium, the chr mium 30v involvedin obtaining from the proposed elecn t t entm y be suppli d as granularferrotrodes a deposited metal in which the constituents chrome orsimilar chromium compound or al y; included in the covering are found inproper promaganese may be s pp as fi a a s portions throughout, nickelas a metallic nickel wire, ribbon or pellets, Electrode metal is usuallymuch more costly etc. I 35 than other metal of generally similaranalysis. It is an object of this invention to provide The high cost ofelectrode metal is due in part to simple and inexpensive apparatus fordepositing, th m l quantities that are made p t n im under the influenceof the new of electric current and the difiiculties encountered in compu through a gap between the end of an electrode some of thespeclalanalyses; The 00st of B180- and the work, metals of differentcomposition, 40 trode metal s always many tlmeimole t h or metal ofsubstantially constant composition total cost of its constltuents intheir read1ly avallbut underdjfl re t c'onditions of deposition fromable commercial forms. Furthermore, while eleca Set of constituentswhereby by Varying the feed trod? metal of Wlde Vanety of analyses m beof any or all of the constituents the required proobtalned all desnableanalyses are not available. portions of the constituents to produce theThis is articular] true of chromium allo s of high ch bmium col itentand of chromium glloys g metal 15 substantlany constantly eposl e of lowcarbon content.

I have found that it is not necessary in order It 15 also i oblect, ofthls mventlon to provide to obtain the results of the prior art toincorslmple and mexpFnslve apparatus for depositing 50 porate n of theconstituents of the finally, metal under the lnfluence of the flow ofelectric posited metal into a metallic electrode, but that currentthrough a gap between the end of an' all of the results of the prior artand results not electrode and the Work, in which t e constituentsobtainable by the prior art, may be obtained in are fed to the gap intheir most economical forms a simple and much more inexpensive manner..at controlled rates to substantially constantly'55 vide simple andinexpensive apparatus for depositing metal under the infiuence of theflow of electric current through a gap between the end of an electrodeand the work, in which a hollow electrode of comparatively cheap andreadily available material that includes a constituent, or constituents,'of the desired deposited metal is used and the remainder of theconstituents required to produce the desired deposited metal aresupplied to the gap separately, but through or partly through the hollowelectrode at such rate or rates that there is substantially constantlydeposited the desired metal; the said remainder of the constituents arealso preferably materials in their most economical forms.

The further objects and advantages or the invention will be betterappreciated from a consideration of the following description ofpreferred modes and apparatus for carrying it out in practice togetherwith the accompanying drawings, in which,

Fig. 1 is a part sectional front view of one form of the apparatus of myinvention,

Fig. 2 is a fragmentary view of the apparatus of Fig. 1, illustratingthe manner of adding electrode sections during the metal depositingoperation,

Fig. 3 is a view similar to Fig. l, of a modified form of apparatus,illustrating the use of a plurality of electrodes, and

Fig. 4 is a view similar to Fig. 3, illustrating the use of a deadelectrode.

The apparatus disclosed, as shown particularly in Fig. 1, includes awelding head Ill of the usual construction and arrangement mounted on asuitable support, not shown, so that it can be moved through a desiredpath relative to work 5. Work Ii may be mounted on an immovable support,also not shown, or it may be mounted on a support capable of movement ina predetermined path relative to welding head It]. Welding head Inincludes a current supply means, such as a welding current generator ora connection to a source of welding current, devices and arrangementsfor controlling the voltage and the amperage of the welding current, andan electrode feed motor that drives electrode feed. wheel l2, togetherwith the usual devices and arrangements for controlling the drive of theelectrode feed motor. It is to be understood that welding head Inincludes all of the usual arrangements and devices which are requiredfor satisfactory operation.

Electrode feed wheel I2 is backed by an idler wheel [3 which serves tomaintain electrode t in contact with feed wheel l2. One side of thecurrent generator, or current supply means, is connected through cableIE to the work It, the other side being connected through cable It to acontact device that passes the electric current to welding electrode M.

While as explained hereinafter, other than hollow electrodes may beused, the apparatus of Fig. l is particularly adapted to the use ofhollow electrodes. Electrode M, as shown, is mad-e up of a plurality ofsections of convenient length which are easily connected together duringthe operation to form an electrode l4 of indefinite length. In thismanner, there is no need to discontinue the operation in order toreplace consumed electrodes. Each length of electrode It is internallythreaded at each end so that it may be connected to the last section inthe apparatus by screwing onto threaded nipple l8. The sections ofelectrode M as shown, are of circular cross-section butany preferredcross-section such as, square, elliptical, and the like may be used aspreferred. Also, while the sections of electrode I 4 are shown asseamless, it is to be understood, that they need not have seamless wallsbut can be made of plate or sheet of proper thickness, shaped asdesired, with the edges joined, or not as preferred. Electrode I4 ispreferably bare but, if desired it may be coated externally orinternally. When electrode i4 is externally coated, it is preferablyprovided with bare contact areas spaced along its length, and a contactdevice ll is provided that is arranged to pass the welding currentthrough the bare contact areas.

Above welding head l0 and in line with the path of electrode I4, issupported hopper Hi, from which material is passed through the hollowelectrode M to the gap between electrode l4 and work It. Hopper l9includes a cylindrical body 20 and a conical bottom 2| that is providedwith an orifice 22. Orifice 22 may be used to meter the material on itsway to electrode M. In such case, orifice 22 is preferably adjustable toprovide for variation in the rate of feed of the material. The material,which may be made up of one or more component materials, is passed tohopper l9 by means of one or more conveyor belts 23.

Conveyor belts 23 may be used as the metering means instead of or inconjunction with orifice 22. In such case, while conveyor belts 23 maybe of any usual construction, they should be provided with means formoving them at a range of predetermined rates and also with means,suchas knives 24, for maintaining a definite depth of material upon them.When the material is metered by belts 23, orifice 22 may be dispensedwith, or made of such size that it will not impede the fiow of materialout of hopper I 9. To prevent largesized particles of the material fromstopping the flow through hopper I9, a screen 25 of suitable mesh isprovided adjacent the top of hopper It.

In order to shut off the fiow ofv material out of hopper l9, as forinstance at the end of the operation or during an interruption thereof,a valve 26 is provided which is adapted to seat on orifice 22. Valve 26is mounted at one end of an articu- I latable bar 2?. The other end ofbar 21 is connected to the armature of an electro-magnet 28 and to aspring 29f The arrangement is such, that the pull of spring 29 tendstoseat valve 28 and electro-magnet 28, when its circuit is closed, unseatsvalve 26. The circuit of the electromagnet 28 is opened and closed bymanipulation of a button switch 30 located on the front of welding headIt. The arrangement may also be such that the circuit of magnet 28 isautomatically opened and closed with the opening and closing of thewelding circuit.

The material passes from orifice 22 into a cylindrical communicatingmember 3i. Member 3| has its top united to the conical portion 2| of'hopp'er l9 andsurrounds the lower end thereof.

Between the ends of member 3| is a diaphragm plate 32 that is providedwith a central orifice 33. Windows or openings 55 are provided in thewalls of member 3| above plate 32 to prevent changes in pressure in thespace between the top of member 3| and plate 32 which pressure changeswould effect the flow of the material. The top of plate 32 is providedwith a conical recess to facilitate the passage of material to andthrough orifice 33.

Orifice 33 is larger than orifice 22 and is, of :ourse, also larger thanan orifice equivalent to aelts 23, when belts 23 are used as themetering means, so that it will have no effect on the meter- .ng of thematerial. Orifice 33 may be closed to shut oi the flow of material tothe lower end of nember 3| by a valve 34 provided for this pur- JOSE.

Valve 34 is mounted at one end of an articuatable bar 35. The other endof bar 35 is coniected to a spring 36 and to the armature of inelectro-magnet 31. ;ending to remove valve 34 from contact with )rifice33 and electro-magnet 31, when its circuit s closed, exerts a pull thatovercomes the pull )f spring 36 and seats valve 34 on orifice 33. [hecircuit of electro-magnet 31 includes a switch 38 that is mounted onasupport member 39 adjacent the path of the electrode at a preietermineddistance from feed wheel I2. Switch 38 may be of any preferredconstruction but should be such that it includes a spring pressed nemberthat is adapted to bear against electrode l4 to open and maintain thecircuit open when ;he end of electrode I4 is above it and to close ;hecircuit and maintain it closed when electrode I4 is out of contact withsaid spring pressed nember. A support member 46 is fixed a shortiistance above support member 39 and has nounted on it a switch 4|similar to switch 38. Switch 4| opens and closes the circuit of an alarmmeans such as bell 42 that is intended to warn the operator of themachine, of. the approaching necessity of adding a section to elec-;rode I4.

To the bottom of cylindrical communicating member 3| is hinged a funnellike member 43 whose spout 44 is, adapted to extend into the ipper endof electrode I4 to pass the 'material from communicating member 3| tothe hollow :enter of electrode l4. Spout 44 is made of such a. lengththat it will extend to a point approxinately level with or preferably .ashort distance aelow the spring pressed member of switch 38.

During the operation of the apparatus, whenever the end of a section ofelectrode I4 passes switch 4|, bell 42 will sound towarn the operatorand call his attention to the fact that a new sectionmust be added toelectrode I4.

When electrode I4 passes switch 38, electromagnet 31 will pull valve 34onto orifice 33 and thus shut off the flow of material to funnel member43. When the end of electrode I4 passes the end of spout 44, theoperator will grasp spout 44 and swing it out of position as shown inFig. 2 and pass a new section of electrode I4 over spout 44'. Spout 44is then brought back to the normal position and the new sectionconnected to the last section of. electrode M by screwing the sectionstogether on the threaded nipple I8. When the new section is swung backto the normal position and into contact with switches 38 and 4|, thecircuits controlled by switches 38 and 4| will again be opened, bell 42will stop sounding and valve 34 will be pulled off orifice 33 toreestablish the flow of the material. It is to be noted that orifice 33is large enough so that it will quickly allow the material accumulatedduring the shut-off period of valve 34 to pass the funnel member 43.Since the operation just described is an extremely. simple one, it canbe performed so quickly that there is in fact no substantialinterruption in the flow of the material to the-bottom of electrode I4.And thus the overall quantity of the materialwill be supplied to the de-Spring 36 exerts a pull posited metal thereby maintaining the analysisuniform.

The apparatus shown in Fig. 3 includes the elements of the apparatus ofFig. 1, above described, and also electrodes 45 and 46, together withtheir feed means and current supply means. It is to be understood thatwhile two electrodes 45 and 46 are mentioned, only one or more than twomay be used. Electrode 45 is driven toward work II by electrode feedwheel 41 that is backed up by idler wheel 48. The motor for driving feedWheel 41, as well as the control arrangements therefore, not shown, arelocated in back of the panel of welding head I. The current supply meansfor electrode 45, not shown, which -may be a Welding current generatoror a connection to an outside source of welding current, together withthe usual control arrangements, are located in back of the panel ofwelding head II). A cable 49 connects the current supply means tocontact means 50 that is adapted to pass the welding current toelectrode 45. The other side of the current supply means for electrode45 may be connected to the work by a separate cable, not shown, or itmay be connected by cable I5. Electrode 46 is driven towards the work Iby electrode feed wheel that is backed up by idler wheel 52. The motorfor driving feed wheel 5| as well as the control arrangements therefore,not shown, are located in back of the panel of welding head I0. Thecurrent supply means for electrode 46, not shown, which may be a weldingcurrent generator or a connection to an outside source of weldingcurrent, together with the usual control arrangements are also locatedin back of the panel of welding head I II. A cable 53 connects thecurrent supply means to contact means 54 that is adapted to pass weldingcurrent to electrode 46. The other side of the current supply means forelectrode 45 may be connected to the work by a separate cable, notshown, or it may be connected by cable I5.

As above stated, electrodes I 4, 45, and 46 may be separately suppliedwith welding current or they may all be supplied from a single source.It is also within the scope of my invention to feed all of theseelectrodes from a single feed motor, by connecting all three of feedwheels I2, 41, and 5| through a suitable train of shafts and gears tothe drive shaft of a single. feed motor. The single feed motor may becontrolled in accordance to the average characteristics of all threearcs or any one or the arcs may be 'used to effect the control. Also,the current and voltage control may also be effected in accordance withthe average characteristics of all three arcs or any one of them.

Welding electrodes I4, 45, and 46 may be arranged on a line as shown orthey may be arranged in any preferred manner, however, it is importantthat they be so closely spaced that all three of them deposit theirmetal in a single pool. Electrodes 45 and 46 may be of any preferredcross-section, they may be solid or hollow and they may be coated orbare. Electrodes 45 and 46 may be of the same analysis or of difierentanalysis as required to produce the desired results.

The apparatus shown in Fig. 4 includes the elements of the apparatus inFig. 1, above described, and also, provides means for feeding, what maybest be called a dead electrode 56, to work II. Dead electrode 56 is fedto work II by a feed wheel 51 that is backed up by an idler wheel 58.Dead electrode 56 is driven by a motor,

electrode 56 may be solid or hollow and of any preferred cross-sectionand may be located in any position relative to electrode l4, however, itis important that it be located sufficiently close to electrode [4 thatit will be fused by the heat generated byJJhe flow of welding currentthrough the gap between electrode l5 and work .ll. Dead electrode 5'6may be of any preferred analysis and while onlyone is shown any numberdesired may be used.

The feed motor for dead electrode 56 maybe dispensed with if desired andfeed wheel 51 driven from the motor that drives feed wheel [2. If thisis done dead electrode 56 may be fed at the same rate as electrode I4 orby the use of any of the well known variable speed ;drive arrangementsit may be fed at any preferred rate. The apparatus of Fig. 4 illustratesthe use of a dead electrode, however, it is'within the scope of thisinvention to combine the apparatus of Figs. 3 and 4 so that liveelectrodes, and 46, as well as dead electrodes 56 may be used with thehollow electrode of Fig. 1.

, any particular metal or alloy but in view of the wide use of steel andcorrosion resistant alloys in the fabrication of metallic'articles, itwill be disclosed in connection with the coating or ve nearing of steelwith corrosion resistantalioys.

The article to be coated or veneered, work II, is substantiallyhorizontally positioned beneath welding head ID with the point, where itis desired to start the first band of veneer 59, beneath the path ofelectrode I4. Electrode I4 is then fed to work II and agap starter suchas a ball of steel wool, a sliver of graphite, an iron nail, etc.,interposed between and in contact with electrode 14 and work II. A lightframe 60 is placed around the area of work'll to be covered by the firstband of veneer 59. Frame 60 is then filled with flux '62 to form ablanket of substantial thickness on work I I over and adjacent the situsof band 59.

Flux 62 may be any fusible compound, or mixture offusible compounds,that do not produce an objectionable amount of gas under the influenceof the discharge ofthe welding current through'the gap between the endof electrode l4 and work H and do not substantially add any undesirableconstituents to or remove any desirable constituents from the depositedmolten metal. Silicates or the components of silicates in general aresuitable particularly if they are dried or calcined or sintered prior touse. However, prefused silicates either neutral, basic or acid aresometimes preferred because of theirpronounced non-gassing character.Manganese silicate, iron silicate, calcium silicate, aluminum silicate,glass and the like, both alone and in mixture have been foundsatisfactory. While fiux 62 should be easily fusible its melting pointshould be high enough to assure that when molten it does not flow tooreadily but remains on, and in the immediate The novel method is notlimited to vicinity of, the molten metal to form a heat retaiiging andgas excluding blanket for the molten me a1.

Flux 62 is preferably used in'the granular form and while greatvariation is possible in the size of the flux particles, it is atpresent preferred to employ a flux the particles of which vary frompowder size to ,4; of an inch and more. The

- blanket of flux 62' is preferably of a. depth sumcient to "submergethe arc, i. e. prevent the visuai and audible manifestations of an arefrom being apparent, and present a substantially quiet top layer offlux. 'It is my present belief that when an arc is submerged it lsnotextinguished and that the welding heat is generated by the arc dischargerather than by the passage of the welding current throngha pool ofmolten flux. However, as this application is a disclosure of fact, it isto be understood that I am not to be bound by any theory or hypothesisas to what takes place beneath the surface of the flux blanket 62. Flux'blankets62 varying in depth from one inch or less to six inches andmore have been found satisfactory. To obtain band 59 with substantiallystraight edges strips 6| may be used. Strips 6| are located near thedesired position of the edges of band 59 and enough space is allowed sothat the molten metal does not contact strips 6!. Strips 6| restrain theflow of the flux and thus restrain the molten metal.

After the blanket of flux 62' is positioned the various controlarrangements are adjusted and set. to maintain thepredetermined voltageand amperage, which in turn maintains a predetermined melting rate ofelectrode and rate of travel along work ,i I, as well as thepredetermined rate of feed of the material from hopper l9 to and throughhollow electrode I4. The welding current circuit is then-closed. Withthe submerged are extremely high energy values may,

be used, thus k. w. and more may satisfactorily be used with electrodesof about diameter. The initial flow of current takes place through thearc starter which upon being consumed leaves a gap between the end ofelectrode [4 and work H. The current flow through the gap melts thesuriace of work II, the end of electrode l4 and some of flux 62. Sincethe fluxes mentioned specifically above, and practically. all knownuseful fluxes, are second degree conductors and hence have a substantialconductivity when molten, it may be that the molten flux forms all or apart of the current path between the end of electrode l4 and work II. Ifsuch is the case, the gap will be filled with molten flux and thewelding heat will result from the passage of the welding current throughthe molten flux. However, if such is not the case, and the probabilitiesare that it is not, the molten flux will form abubble'in which an arc ispresent that plays between the end of electrode l4 and work ll. As thepassage of current continues the metal fused from electrode l4 and fromwork I I, as well as the a metal that results from the material passingto the gap between the end of the electrode I4 and work ll coalescesinto a unitary molten pool.

After the initial passage of current work II or welding head I0, orboth, are moved to cause the molten metal to deposit on ,work II in theform of a wide band 59. When the work I l and electrode [4 move relativeto each other the fiux melted by the welding heat remains on and coversthe molten metal. Because of the heat retaining capacity or fiux 62 aswell as the welding heat generated at the gap, the molten metal spreadswork II. The operation is then allowed to continue until the full lengthor width, of work II is covered by band 59. It is of course to beunderstood that during the band depositing operation sections ofelectrode I4 are added as required in'the manner previously described.The remainder of the bands 59 required to completely cover the surfaceof work H are then deposited. The

procedure is the same except that only one strip 6| is used, on the sideopposite to the already deposited band or hands 59, and the new bands 59are so located that their contiguous edges overlap so as to assure acontinuous and properly fused surface as well as proper fusion into.work ll.

1 The band forming operation with the apparatus of Figs. 3 and 4 issubstantially identical with that just described and a detaileddescription of the operation with each of these apparatus is not thoughtnecessary.

The penetration of the veneer 59 into work H,

' or as may be otherwise. stated, the amount of -(1) rate of travel ofthe electrode relative to metal of work II that finds its way intoveneer 59, is an important factor in obtaining a veneer 59 of desiredanalysis. Penetration is affected by many factors among which may bementioned,

the work, (2) the current density and total energy dissipation at thegap between the electrode and the work, (3) the temperature of the workand (4) the position of the work'with respect to the. horizontal.results in .a higher penetration than a low rate. High current densitiesgive higher penetration than lower current densities; the same effect isnoticed if the current density per unitof metal area is maintainedconstant and the area'of the electrode is changed, an electrode of smallarea will give a greater penetration than an electrode of larger area.For a given set of conditions the higher the temperature of the work,the greater the penetration obtained, thus the penetration may beincreased by preheating the work. Also, for a given set of conditionsthe penetration may be varied by tilting the work relative to thehorizontal. If the work is tilted so that the molten metal tends to flowdown hill in,back of the electrode the penetration is increased; if thework is tilted so that the molten metal tendsto flow down hill ahead ofthe electrode the penetration is decreased. By controliiihg thesefactors almost any penetration desired? may be obtained. In

practice, penetrations ranging from 5 to 95% have been'obtained, i. e.veneers have been deposited that extended from 95 to 5% below theoriginal surface of the work.

Because of the number of factors involved and the variations of eachfactor possible, no attempt will be made to set forth the specificmanner for obtaining any particular penetration. It is believed that theabove explanation will enable any skilled worker in the art to attainany desirable penetration in the range set forth.

In veneering steel with corrosion resistant alloys ordinary mild steelpipe with a carbon content in the neighborhood of 0.03% or less is apreferred material for electrode l4., The chro miiim. required ispreferably supplied by using ferro-chrome as the material passed to thegap between electrode l4 and work ll through electrode l4. Ferro-chromeof commerce usually contains, in round numbers 70% chromium and 30% ironand can be obtained with carbon contents-ranging from 0.06% to 6.0%.When nickel In general a high rate of travel passed through hollowelectrode I 4. The nickel may be metallic nickel in granular or powderform orit may be some suitable nickel compound or alloy in the granularor powder iorm.

It should be evident to anyone skilled in the art that a wide range ofchromium-iron and chromium-iron-nickel alloy veneers are possible withthe materials above mentioned simply by varying the penetration, theelectrode feed, and the feed of the material passed through theelectrode. In depositing any particular veneer, as for instance a 16%chrome veneer with a maximum of 0.12carbon a penetration which allowsthe desired results to be obtained is first. determined. With the workll of 0.25 carbon steel a' 3 40% penetration is satisfactory.Thispenetration will cause work II to supply 40 parts, based on 100 asthe total parts, of the iron to the final alloy and .10 part of carbon.If a ferro-chrome of 0.06 carbon is chosen the 16 parts of chromiumrequired will be supplied by 22.8 parts of ferrochrome. This amount offerro-chrome will sup ply 6.8 parts of iron to the'final alloy and 0.013part of carbon. If a mild steel of .02 carbon is used as electrode I4,the remaining 37.2 parts of iron required will be supplied by an equalnumber ofparts of electrode M. The electrode I4 will in this case add.006 part'of carbon to the alloy. Thus, the final veneer will containthe 16% 'chromium required and will have a carbon content of. 0.119%.This analysis will be obtained by so adjusting and controlling theoperation that 37.2 lbs. of electrode l4, and 22.8 lbs. of ferrochromeare alloyed with 40 lbs. of the metal of work H fused by the currentdischarge. It is to be noted here that there is a loss of constituentsduring the operation due to the absorption by the flux and other causesso that in order to obtain the results indicated it will be necessary toincrease the quantities above the values given to take care of thelosses. It is sometimes desirable to add some of the alloyingconstituents through flux 62 by incorporating them in .flux 62. In suchcases the quantity of the materials fed to the gap will be modifiedaccordingly.

With the materials specifically disclosed above a wide change inanalysis of alloy is possible. Thus, the carbon content of the alloy maybe reduced materially by using lower penetrations. The chromium contentmaybe varied by changing the relative rate of feed of the ferro-chromeand melting rate of the electrode. By choosing the proper-rates of feedand the proper penetra-- tion, chromium alloys may be deposited with .06carbon and less and also with 26% chromium and more.

'In carrying'out the novel method of this ap-;

thus in depositing a high nickel, nickel-chrome-' iron alloy, thepenetration chosen may be such that the base metal will supply the majorproportion of the iron required. 'In such case it would be preferable tomake the hollow electrode of pure nickel or some suitable nickel alloy.Thus,

' in interpreting this disclosure it is to be remembered that itcontemplates the use of the materials for electrodes and feedmaterialthrough the electrode l4 best suited to give the desiredresults.

In using the apparatus of Figs. 3 and 4 the method above described isalso carried out, however with these apparatus further variations of themethod are possible. Thus, if it is desired to deposit an alloy havingalloying constituents in minor proportions as, for instance, a 4-6chrome steel, a portion of the steel required may be supplied throughelectrodes 45 and/or 46 and/or dead electrode 56. These apparatus arealso suited to the cases Where cheap metal is available having acomposition not very much different from the desired alloy. In thelatter cases all or some of the electrodes may be made of the availa-,

ble material and the rest of the constituents required for the desiredalloy fed through the hollow electrode.

, I claim:

1. In apparatus for depositing metal under the influence of the flow ofelectric current through a gap between the end of an electrode and thework, in -combination, a hollow electrode, means for feeding said hollowelectrode at a controllable predetermined rate to the work, electriccurrent supply means connected to the electrode and to the work, ahollow member adapted to extend into said hollow electrode, materialmetering means in communication with said hollow member adapted to passmaterial to said hollow member at a predetermined rate, and means forshutting off at will communication between said metering means and saidhollow member, said shutting oif means being arranged to accommodate thematerial metered during the period that said hollow member and saidmetering means are out of communication and torelease said ac--cumulated material to said hollow-member at a rapid rate whencommunication is againestablished.

2. In apparatus for depositing metal under the influence of the flow orelectric current through 'a gap between the end of an electrode and thework, in combination, a hollow electrode including a plurality ofconnectable seotions,' means for feeding said hollow electrode at acontrollable rate to the work, electric current supply means connectedto the electrode and to the work, a hollow member adapted to extend intothe top end of said electrode on its way to the work, a materialmetering device, and a hollow communicating member attached to saidmetering device, said communicating member having said hollow memberhingedly connected thereto -whereby said hollow member may be swung outof the path of the electrode for the addition of new sections to theelectrode as needed, saidcommunicating member including an operatableshutofi device adapted to cut off the flow of material from saidmetering device to said hollow member during the addition of electrodesections and to pass the material accumulated during the shutoff periodat a rapid rate to said hollow member when communication is againestablished between said hollow member and said metering device.

3. In apparatus for depositing metal under the influence of the flow of.electric current through a gap between the end of an electrode and thework, in combination, a hollow electrode, including a plurality ofconnectable sections, means for feeding said hollow electrode at acontrollable rate to the work, electric current supply means connectedto the electrode and to the work, a hollow member adapted to extend intothe top end of said electrode on its way to the work, a

material metering device, and a hollow communieating member attached tosaid metering device,

the addition of electrode sections and to pass the material accumulatedduring the shutoff period at a rapid rate to said hollow member whencommunication is again established between said hollow member and saidmetering device, said communicating member having pressure equalizingapertures therein to prevent changes in the metering and the flow ofsaid material due tov changes of pressure in said communicating memberand in said hollow member.

4. In apparatus for depositing metal under the influence of the flow ofelectric current through a gap between the end of an electrode and thework in combination, a hollow electrode, means for feeding said hollowelectrode to the work at a controllable predetermined rate, currentsupply means connected to said electrode and to the work, acommunicating member, metering means controlling the passage of materialto said member, operatable means for stopping the passage of thematerial to said communicating member, a hollow member adapted to extendinto the end of said electrode on its way to the work, said member beingin communication with said communicating member and being adapted topass material from said communicating member to said gap through saidhollow electrode, operatable means in said communicating member forstop-. ping passage of material to said hollow member, said secondmentioned operatable means being arranged to accumulate the materialpassing to it during the stoppage of communication between thecommunicating member and the hollow member and to pass said material tothe hollow member upon reestablishment of communication, said hollowmember being connected to said communicating member the connection beingsuch that said hollow member may be swung out of and into the path ofthe electrode for the addition of electrode sections.

5. In apparatus for depositing metal under the influence of the flow ofelectric current through a gap between the end of an electrode and thework in combination, a hollow electrode, means for feeding said hollowelectrode to the work at a controllable predetermined rate, currentsupply means connected to said electrode and to the work, acommunicating member, metering means controlling the passage of materialto said member, operatable means for interrupting at will the passage ofmaterial to said communicating member, a hollow member having one end incommunication with said communicating member and the other end extendinginto said hollow electrode on its way to the work, said hollow memberbeing arranged to be swung out of and into the path of the electrode toallow addition of electrode sections as required, a second operatablemeans for interrupting the passage of material to said hollow member,and means including econd operatable means to open communication rhenthe end of the electrode again extends poseriorly of said point. I

6. In apparatus for depositing metal under the ifluence of the flow ofelectric current through gap between the end of an electrode and theork, in combination a hollow electrode made up i connectable sections,an electrode feed means, lectric currentrsupply means connected tothelectrode and to the work for passing electric urrent through said gap,material supply means,

movable hollow member in communication with lid supply means and adaptedto extend into aid hollow electrode to feed material thereto for assageto said gap, said hollow member being lovable away from said electrodefor placing of lectrode sections thereon and being movable into ne withsaid electrode for connection of sections iereto. 1 Y

7. In an apparatus for depositing metal under me influence of electriccurrent discharge irough a gap between an electrode and the work,

1e combination with an electrode having a pasigeway, means forcontinuously feeding said lectrode to the gap, electric current supplyleans connected to the electrode and the work, separate metalsupplymeans, means for feedig metal from the metal supply means to theassageway in the electrode, means for interipting the supply of metal tothe electrode withit varying the ultimate metal supplied to the 1p.

8. In an apparatus for depositing metal under ie influence of electriccurrent discharge irough a gap between an electrode and the work,

ie combination with an electrode having a pas-.

lgeway, means for continuously feeding said ectrode to the gap, electriccurrent supply means mnectd to the electrode and the work, a sepaitemetal supply means, means for feeding metal om the metal supply means tothe passageway in i8 electrode, means for interrupting the supplymetalto the electrode, including a reservoir Ir accumulating metalsupplied during the interlption period, said interrupting means adaptedsupply metal from ,the supply means and aclmulated metal without varyingthe ultimate etal supplied to the gap.

9. In an apparatus for depositing metal under ityiof electrodespositioned substantially transversely to the direction of relativemovement of the electrodes and the work, one of said electrodesproviding a-passageway, a separate metal supply means, and means. forcontrolling the feed of metal from the separate metal supply to theelectrode having said passageway.

.11. In an apparatus for depositing metal under the influence ofelectric current discharge through gaps between a plurality ofelectrodes and the work, including in combination a plurality of solidelectrodes and one electrode having a passageway, a separate metalsupply means, and means for separately controlling the feed of saidsolid electrodes and the metal feed from said separate metal supply, andmeans-for supplying current to said electrode.

12. In an apparatus for depositing metal under the influence of anelectric current discharge through a gap between an electrodeand aworkpiece, including in combination, a conduit having a substantiallyunbroken periphery, said conduit being in the form. of a consumablemetal elecpipe electrode of substantially unbroken periphery, means forfeeding said electrode to the gap, current supply means contacting saidelectrode and the workpiece for passing current through said gap to fusethe electrode, a supply of metal in particle form, controllable'meansfor feeding said metal in said supply to said electrode for conveyancetherethrough without substantial loss tov the gap beneath said flux tobe fused thereat with the metal of the electrode.

14. In an apparatus for depositing metal under the influence of anelectric current discharge through a gap betweenan electrode and aworkpiece, including in combination, a conduit having a substantiallyunbroken periphery in the form of a consumable metal electrode, meansfor feeding said electrode to the gap at a controllable rate,

current supply means contacting said electrode and the workpiece forpassing current through said gap to fuse the electrode, metal supplymeans, and separate means for feeding metal in said supply to saidconduit-to be directed thereby to the gap to be fused with the metal ofthe electrode,

said separate means for feeding said metal being controllable to effecta rate of feed of the metal independent of the rate of feed of theelectrode.

ROBERT K. HOPKINS.

